海南岛中部丘陵地区植被恢复过程中凋落物动态及土壤碳氮含量变化

Dynamics of plant litter and change of soil carbon and nitrogen contents in the process of the vegeta-tion restoration in hilly land in central Hainan Island

关键词:  凋落物分解  植被恢复  海南岛  丘陵

Key words:  litter decomposition  vegetation restoration  Hainan Island  hilly land

摘要:

为探究海南岛中部丘陵地区植被恢复过程中凋落物分解动态和土壤碳氮含量变化,采用时空互代法,在琼中湾岭地区同时具有经自然恢复的草丛、灌丛、次生林和人工恢复的马占相思林4种植物群落的两个山坡采用凋落物袋法进行凋落物交互分解实验。结果表明:4类型凋落物在同一样地中分解时,灌丛凋落物肖梵天花分解速率最高; 同一种类凋落物在4个样地中分解时,在灌丛样地的分解率较高,而在3个自然植被样地中,分解速率为灌丛>草丛>次生林,显示随着植物群落进展演替的进程,凋落物分解速率呈现先增加后降低的趋势; 马占相思凋落物和在马占相思林样地分解凋落物的分解率均低于次生林。土壤碳氮含量变化不显著,但有随植被恢复进程而增加的趋势。

Abstract:

To explore the dynamics of plant litter decomposition and the changes of soil carbon and nitrogen in the hilly land region in central Hainan Island,we conducted an experiment of translocation litter decompositon on the ground in situ and ex situ among the four plant communities of grassland,shrubland,secondary forest and Acacia mangium plantation distibuted in two hilly slopes. The results were as follows: The litter decomposition rates of the 4 types of litter were significantly different in the same site,and the decomposition rate of U.lobata litter was the highest. The decomposition rates of a same type litter were the highest in shrubland among the 4 plant communities,while in the 3 natural plant communities were in the order of shrubland>in grassland>in secondary forest,which indicated that with the progressive succusion the decomposition rates were higher in the eralier stage and then lower in the later stage. The decomposition rates of all litters were lower in A.mangium plantation than in secondary forest. The total contents of carbon and nitrogen in soils were trend to increase with the process of vegetation restoration,i.e.secondary forest>shrub land>grassland.